Adults over 75 years of age comprise the fastest growing group receiving dialysis. Unfortunately, many of these patients experience significant functional impairment and declines in quality of life (QOL) after starting dialysis. Because QOL informs treatment decisions (e.g., shared decision-making about dialysis modality, dialysis discontinuation, or length of therapy) and treatment effectiveness (i.e., research that measures the effect of a treatment on QOL), accurate QOL measurement is essential. The Kidney Disease Quality of Life (KDQOL-36) instrument is widely used in clinical practice and research, but it has not been validated in older patients treated with dialysis, in whom floor effects may be problematic. Also, it is not known if the KDQOL-36 adequately measures QOL domains of highest importance to older adults (e.g., spirituality, physical environment, and end of life domains). My long-term goal is to develop a patient-centered approach to improving quality of life for older dialysis patients. As a first step towards this goal, the objectives of this applicaion are to improve the measurement of QOL in older dialysis patients. The aims of this application are to: 1) determine the reliability and validity of the KDQOL-36 in older patients, and 2) determine additional QOL domains not included in the KDQOL-36 that older patients receiving dialysis view as highly important. In the first aim, the KDQOL-36's psychometric properties will be evaluated using data from a large cohort of older patients receiving dialysis. In the second aim, patient perspectives on QOL will be obtained through semi-structured interviews of local older patients receiving dialysis and their caregivers. Upon completion of these aims, I will have preliminary data to develop a novel, valid, and comprehensive instrument (or set of instruments) that incorporates the values and preferences of this population to measure QOL. Improving the measurement of QOL among older dialysis patients is critical for future intervention and cost-effectiveness studies.